The present invention relates generally to the field of virtual machines, and more particularly to optimizing the process of virtual machine decommission to reclaim resources.
In computing, a virtual machine (VM) is an emulation of a particular computer system. Virtual machines operate based on the computer architecture and functions of a real or hypothetical computer, and their implementations may involve specialized hardware, software, or a combination of both. Virtual machines can be Linux Containers, Dockers, or ZeroVM, etc.
Classification of virtual machines can be based on the degree to which they implement functionality of targeted real machines. That way, system virtual machines (also known as full virtualization VMs) provide a complete substitute for the targeted real machine and a level of functionality required for the execution of a complete operating system. On the other hand, process virtual machines are designed to execute a single computer program by providing an abstracted and platform-independent program execution environment.
Some computer architectures are capable of hardware-assisted virtualization, which enables efficient full virtualization by using virtualization-specific hardware capabilities, primarily from the host CPUs.
A zombie VM is a VM that is not functioning properly in a software environment, but continues to operate, sucking up resources and providing no value. The term zombie VM is sometimes used interchangeably with the term orphaned VM, which is a machine that has been disconnected from its host. However, with a zombie VM, there is the implication that the VM is still actively using resources since it is still connected to its host. Along with incorrectly configured VMs, system administrators also look for disconnected or otherwise useless VMDK files, the files held on these systems, to try to clean up and prevent what is often called VM sprawl. VM sprawl happens when more VMs are deployed or created than are necessary. This occurs largely because of inefficiencies in building out systems and because of changes in systems over time, where, without rigorous analysis and constant management, resources become tied up in obsolete configurations.